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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>19.11. Secure TCP/IP Connections with SSH Tunnels</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="gssapi-enc.html" title="19.10. Secure TCP/IP Connections with GSSAPI Encryption" /><link rel="next" href="event-log-registration.html" title="19.12. Registering Event Log on Windows" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">19.11. Secure TCP/IP Connections with <span class="application">SSH</span> Tunnels</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="gssapi-enc.html" title="19.10. Secure TCP/IP Connections with GSSAPI Encryption">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="runtime.html" title="Chapter 19. Server Setup and Operation">Up</a></td><th width="60%" align="center">Chapter 19. Server Setup and Operation</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 15.7 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="event-log-registration.html" title="19.12. Registering Event Log on Windows">Next</a></td></tr></table><hr /></div><div class="sect1" id="SSH-TUNNELS"><div class="titlepage"><div><div><h2 class="title" style="clear: both">19.11. Secure TCP/IP Connections with <span class="application">SSH</span> Tunnels</h2></div></div></div><a id="id-1.6.6.14.2" class="indexterm"></a><p>
   It is possible to use <span class="application">SSH</span> to encrypt the network
   connection between clients and a
   <span class="productname">PostgreSQL</span> server. Done properly, this
   provides an adequately secure network connection, even for non-SSL-capable
   clients.
  </p><p>
   First make sure that an <span class="application">SSH</span> server is
   running properly on the same machine as the
   <span class="productname">PostgreSQL</span> server and that you can log in using
   <code class="command">ssh</code> as some user;  you then can establish a
   secure tunnel to the remote server.  A secure tunnel listens on a
   local port and forwards all traffic to a port on the remote machine.
   Traffic sent to the remote port can arrive on its
   <code class="literal">localhost</code> address, or different bind
   address if desired;  it does not appear as coming from your
   local machine.  This command creates a secure tunnel from the client
   machine to the remote machine <code class="literal">foo.com</code>:
</p><pre class="programlisting">
ssh -L 63333:localhost:5432 joe@foo.com
</pre><p>
   The first number in the <code class="option">-L</code> argument, 63333, is the
   local port number of the tunnel; it can be any unused port.  (IANA
   reserves ports 49152 through 65535 for private use.)  The name or IP
   address after this is the remote bind address you are connecting to,
   i.e., <code class="literal">localhost</code>, which is the default.  The second
   number, 5432, is the remote end of the tunnel, e.g., the port number
   your database server is using.  In order to connect to the database
   server using this tunnel, you connect to port 63333 on the local
   machine:
</p><pre class="programlisting">
psql -h localhost -p 63333 postgres
</pre><p>
   To the database server it will then look as though you are
   user <code class="literal">joe</code> on host <code class="literal">foo.com</code>
   connecting to the <code class="literal">localhost</code> bind address, and it
   will use whatever authentication procedure was configured for
   connections by that user to that bind address.  Note that the server will not
   think the connection is SSL-encrypted, since in fact it is not
   encrypted between the
   <span class="application">SSH</span> server and the
   <span class="productname">PostgreSQL</span> server.  This should not pose any
   extra security risk because they are on the same machine.
  </p><p>
   In order for the
   tunnel setup to succeed you must be allowed to connect via
   <code class="command">ssh</code> as <code class="literal">joe@foo.com</code>, just
   as if you had attempted to use <code class="command">ssh</code> to create a
   terminal session.
  </p><p>
   You could also have set up port forwarding as
</p><pre class="programlisting">
ssh -L 63333:foo.com:5432 joe@foo.com
</pre><p>
   but then the database server will see the connection as coming in
   on its <code class="literal">foo.com</code> bind address, which is not opened by
   the default setting <code class="literal">listen_addresses =
   'localhost'</code>.  This is usually not what you want.
  </p><p>
   If you have to <span class="quote"><span class="quote">hop</span></span> to the database server via some
   login host, one possible setup could look like this:
</p><pre class="programlisting">
ssh -L 63333:db.foo.com:5432 joe@shell.foo.com
</pre><p>
   Note that this way the connection
   from <code class="literal">shell.foo.com</code>
   to <code class="literal">db.foo.com</code> will not be encrypted by the SSH
   tunnel.
   SSH offers quite a few configuration possibilities when the network
   is restricted in various ways.  Please refer to the SSH
   documentation for details.
  </p><div class="tip"><h3 class="title">Tip</h3><p>
    Several other applications exist that can provide secure tunnels using
    a procedure similar in concept to the one just described.
   </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="gssapi-enc.html" title="19.10. Secure TCP/IP Connections with GSSAPI Encryption">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="runtime.html" title="Chapter 19. Server Setup and Operation">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="event-log-registration.html" title="19.12. Registering Event Log on Windows">Next</a></td></tr><tr><td width="40%" align="left" valign="top">19.10. Secure TCP/IP Connections with GSSAPI Encryption </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 15.7 Documentation">Home</a></td><td width="40%" align="right" valign="top"> 19.12. Registering <span class="application">Event Log</span> on <span class="systemitem">Windows</span></td></tr></table></div></body></html>